Plug-in air purifier



FIG. 1 is a front perspective view of a plug-in air purifier showing my new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a side elevation view of one side thereof;

FIG. 4 is a side elevation view of one side thereof;

FIG. 5 is a front elevation view thereof;

FIG. 6 is a rear elevation view of the other side thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof. 

The ornamental design for a plug-in air purifier, as shown. 